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Localization of tumor necrosis factor receptor messenger RNA in normal and herpes simplex virus-infected mouse eyes
E T Cunningham1, A Stalder, P P Sanna
1Francis I. Proctor Foundation, University of California, San Francisco 94143-0944, USA.
Purpose:
To investigate the distribution of p75 and p55 tumor necrosis factor receptor (TNFR) mRNA in normal mouse eyes and in mouse eyes acutely infected with McKrae strain herpes simplex virus (HSV).
Methods:
In situ hybridization with antisense 35S-labeled riboprobes for p55 and p75 TNFR subtypes was used in uninfected and HSV-infected mouse eyes. Controls included the use of sense riboprobes and corneas inoculated with vehicle alone.
Results:
In uninfected and infected mouse eyes, in situ hybridization produced an autoradiographic signal for mRNA, encoding both p75 and p55 over the corneal endothelium, iris, ciliary body, choroid, and arachnoid layers of the optic nerve sheath. In addition, the signal was observed over scattered cells at the vitreoretinal interface. Signal for p75, but not p55, was observed over cells in the retinal ganglion cell layer. Acute HSV infection was accompanied by an intense leukocytic infiltrate in the conjunctiva, the corneal subepithelium and stroma, the anterior and posterior chambers, the iris root and ciliary body, and the vitreous cavity. In this setting, increased p75 and p55 mRNA signal was correlated closely with the number and location of receptor-bearing white blood cells. Signal over control sections hybridized with sense p75 and p55 TNFR cRNA probes was comparable to background. Signal over control eyes inoculated with sterile vehicle showed slight increased signal in the immediate vicinity of the traumatic keratitis, but otherwise it was comparable to that observed in uninfected animals.
Conclusions:
The observed distribution of p75 and p55 TNFR mRNA in normal and acutely infected mouse eyes, and particularly over the heavily vascularized uveal tract and over cells at the vitreoretinal interface, supports a role for TNF as a mediator of intraocular inflammation, perhaps as a key regulator of the blood-ocular barrier.
Insights
Tumor necrosis factor receptor (TNFR) mRNA, p75 and p55, is found in normal mouse eyes. Herpes simplex virus (HSV) infection increases TNFR mRNA, especially in infiltrating white blood cells, suggesting a role in ocular inflammation.
Area of Science:
- Ophthalmology
- Immunology
- Molecular Biology
Background:
- Tumor necrosis factor (TNF) plays a role in inflammation.
- TNF receptors (TNFRs) mediate TNF signaling.
- Understanding TNFR distribution is crucial for inflammatory eye diseases.
Purpose of the Study:
- To map the distribution of p75 and p55 TNFR mRNA in normal and herpes simplex virus (HSV)-infected mouse eyes.
- To investigate the role of TNFRs in ocular inflammation.
Main Methods:
- In situ hybridization using 35S-labeled riboprobes for p75 and p55 TNFR subtypes.
- Analysis of uninfected and HSV-infected mouse eyes.
- Control groups included sense riboprobes and vehicle-inoculated corneas.
Main Results:
- p75 and p55 TNFR mRNA detected in corneal endothelium, iris, ciliary body, choroid, and optic nerve sheath.
- Signal also observed at the vitreoretinal interface and in the retinal ganglion cell layer (p75 only).
- HSV infection led to increased TNFR mRNA, correlating with white blood cell infiltration.
Conclusions:
- TNFR mRNA is present in various ocular tissues.
- Increased TNFR mRNA during HSV infection suggests a role in mediating intraocular inflammation.
- TNFRs may be key regulators of the blood-ocular barrier.